The present invention relates to a heat insulating container comprising an inner container body and a sleeve which has cut edges extending transversely to the circumferential direction of the container and being attached to the circumferential wall of the inner container by attaching surfaces. The present invention also relates to a process for making a heat insulating container comprising an inner container body and a sleeve from a flat blank and wrapped around the inner container body.
U.S. Pat. No. 5,226,585 describes a known container in which two attaching surfaces extend circumferentially of the container. These attaching surfaces are arranged at the border areas of two sleeve cut edges which extend in circumferential direction. Two other sleeve cut edges extend transversely to the circumferential direction, whereby the border area of one cut edge overlaps the border area of the other cut edge. A further attaching surface is arranged on the inner border area.
It is an object of the present invention to reduce working time and/or the amount of material needed for making a container without lessening the insulating effect.
This object has been achieved in accordance with the present invention by arranging all attaching surfaces extending transversely to the circumferential direction.
With regard to the production process, this object has been achieved in that the blank is wrapped around the inner container body such that two cut edges come to lie facing each other, transversely to the circumferential direction. Thereafter, the blank is attached at those areas bordering the named cut edges, to the inner container body in one procedural step.
Due to the sleeve being attached transversely to the circumferential direction, attaching surfaces extending in circumferential direction are superfluous. Attaching surfaces which extend transversely to the circumferential direction can be applied to the sleeve in less working time and usually with less material than attaching surfaces which extend in circumferential direction. This attachment is entirely sufficient. The sleeve's function is primarily that of heat insulation. This heat insulation function is not impaired by the attachment methodology of the present invention.
The invention can be applied to any type of container, regardless of form, while a variety of materials can be used for the container. The sleeve can be made of one material layer or comprise several layers.
In one advantageous embodiment, at least a part of the attaching surfaces are arranged at those edge areas which border the cut edges extending transversely to the circumferential direction. The advantageous arrangement guarantees a secure holding of the longitudinal ends of the sleeve. Additional measures to ensure against detachment of the longitudinal ends, which are especially at risk, are thus not necessary.
In a further embodiment of the present invention, at least one additional attaching surface is arranged at a distance to the cut edges extending transversely to the circumferential direction. A more secure attachment of the sleeve is thus ensured. It is hereby purposeful if the at least one additional attaching surface is arranged halfway between the distance to the cut edges extending transversely to the circumferential direction. Further attaching surfaces at a distance to the cut edges are then, as a rule, superfluous.
In a still further advantageous embodiment of the invention, the sleeve is attached to the circumferential wall of the inner container by a tensile stress working in circumferential direction. This ensures that the sleeve also lies on the inner container outside of the attaching surfaces and that those edges bordering the cut edges extending in circumferential direction do not lift off.
In yet another advantageous embodiment of the invention, the cut edges extending transversely to the circumferential direction face each other so that those edges bordering thereon do not overlap each other. The attaching surfaces of both border areas are then in contact with the circumferential wall of the inner container. The attachment can therefore be simplified as, for example, the attaching structure for both border areas can be applied to the inner container. In addition thereto, the border areas are less at risk of lifting off owing to the lack of overlap. This applies in particular when the sleeve has been wound in abutting relationship. There is the further advantage that the containers, as a result of the lack of overlap, do not thicken at any point, and are thus easy to handle. For example, they can be stacked.
In still another advantageous embodiment of the present invention, the sleeve has profilings projecting outwardly or inwardly. The profilings can be arranged on a single material layer, if the sleeve comprises plurality of material layers. Hollow spaces arise between the inner container and the inside of the sleeve owing to the profiling, and this arrangement results in an increase in heat insulation. It is thereby possible to use thinner material which is easy to work with. It is advantageous to arrange the profilings proportionally over the surface of the sleeve.
It is practical to arrange the attaching surfaces onto profilings. The amount of attaching structure can thus be reduced. It is not necessary, although of course possible, to also fill the hollow spaces bordering on the profilings with the attaching structure. In another advantageous feature, the profilings can be arranged on those areas bordering the cut edges, and attaching surfaces can be provided on the profilings. In many cases it can be more economical to arrange the profilings in any way desired. The attaching surfaces are then arranged independent of the position of the profilings.
It is also advantageous to arrange at least a number of the profilings transversely to the circumferential direction. This results in the attaching surfaces, which extend transversely to the circumferential direction, lying on the profilings. This applies also when the position of the profilings is not fixed during application the sleeve. In the latter case, the attaching surfaces must have a sufficient extent in circumferential direction, so that they too surround the profilings.
It is practical for the sleeve to have hollows which correspond to the projecting profilings. The hollows are situated on side of the sleeve opposite the profilings, or on the material layer of the sleeve which comprises the profilings. The profilings and hollows can be simply made, for example by stamping.
It is further advantageous to form the profilings as small round protrusions which can project inwardly or outwardly. It is useful to cover the material layer comprising the small round protrusions with an additional material layer on the outside.
In another still further advantageous embodiment of the present invention, the profilings are formed as ridges extending transversely to the circumferential direction. These ridges can be made in a simple way by stamping, whereby groove-like hollows arise which correspond to the ridges. It is particularly advantageous when the ridges project outwardly.
The profilings can take many forms. The profilings can, for example, extend wave-like in circumferential direction, so that corrugated cardboard could be used for the sleeve.
It is advantageous for the sleeve to comprise only one heat insulating material layer. A good insulating container can hereby be made with less work and material. This embodiment is, for example, then practical when it is provided with ridges projecting inwardly and extending transversely to the circumferential direction. Although visible from the outside, the groove-like hollows do not impair the insulating effect. When handling the container, the user does not come into contact with the inside of the hollows, provided that the hollows are not too wide.
It is practical for at least one of the sleeve and the inner container to comprise at least one material layer of paper or cardboard. These materials are particularly suitable for the production of a heat insulating container because they are easy to process.
In an further advantageous embodiment of the present invention, the attaching surfaces border directly onto the cut edges.
In yet another advantageous embodiment of the present invention, the sleeve is attached to the circumferential wall of the inner container by means of a gluing agent or by heat-sealing.
In one currently preferred embodiment of the present invention, the attaching surfaces, which are situated in the area of the cut edges which extend transversely to the circumferential direction, are attached to the circumferential wall of the inner container by a joint adhesive, such as, for example, glue or heat-sealable synthetic material. The joint adhesive makes possible the attachment of the sleeve to the above mentioned attaching surfaces in one procedural step.
If glue is used as the joint adhesive, a uniform layer thereof can be applied, transversely to the circumferential direction, to the circumferential wall of the container. The attaching surfaces can then be pressed against the glue layer in the area of both cut edges. A glued joint arises on each attaching surface.
If heat-sealable synthetic material is used as the joint adhesive, it is possible to apply a uniform plastic layer, extending transversely to the circumferential direction, to the circumferential wall of the container, which is melted into a heat sealing joint. This heat sealing joint joins the attaching surfaces in the area of both cut edges to the inner container.